1. Field of the Invention
The present invention relates to a mobile communication system. More particularly, it relates to a mobile communication system for determining optimal associated parameters of the parallel combinatory spread-spectrum scheme, and a radio control station, base station and mobile station for the system, and a parameter determination method employing the parallel combinatory spread-spectrum scheme.
2. Description of the Related Art
In mobile communication systems, a method for assigning associated parameters of the parallel combinatory spread-spectrum scheme is known (see, for example, Jpn. Pat. Appln. KOKAI Publication No. 2002-152086 (pages 7 to 11; FIGS. 1 to 8).
Jpn. Pat. Appln. KOKAI Publication No. 2002-152086 discloses a technique for varying, in accordance with a transmission rate requested for data transmission, at least one of the associated parameters, such as spreading code length n, number m of spreading code candidates, and number (multiple number) k of selected spreading codes.
Jpn. Pat. Appln. KOKAI Publication No. 2002-152086 discloses another technique for selecting one of the combinations, which provide predetermined transmission rates, of associated parameters, such as spreading code lengths n, number m of spreading code candidates, and number k of selected spreading codes. The one combination is selected in light of the transmission accuracy required for data transmission, and/or the number of users to whom the number m is assigned, and/or the states of transmission channels.
In the conventional mobile communication system described in Jpn. Pat. Appln. KOKAI Publication No. 2002-152086, excessive resources may be required in base stations, since the system resources and radio resources assigned to each base station are not determined in consideration of overall resource saving.